The present invention relates to a semiconductor device and a method for manufacturing the same. More specifically, the present invention relates to a process of forming a bar-shaped protruding portion at the bottom of a recess region to increase channel length and width of a gate so as to improve the process margin of a semiconductor device, thereby improving the electric characteristics of a semiconductor device.
Due to the high integration of semiconductor devices, the process margins for forming an active region and a device isolation film has decreased. Also, as the width of gates has become smaller, the channel length becomes smaller, which results in a short channel effect, degrading electric characteristics of the semiconductor devices. In order to prevent short channel effects, a recess gate has been used which increases the channel length of the gate by etching a gate location region at a predetermined thickness to increase the contact area between the active region and the gate.
FIG. 1 is a plane diagram illustrating a conventional semiconductor device. Referring to FIG. 1, an active region 20 and a device isolation film 30 are formed over a semiconductor substrate 10. Then, a recess region 60 is formed where the active region 20 of a gate location region 75 is etched.
FIG. 2 shows a cross-section A-A′ in FIG. 1. A gate 70 is formed over a recess region 60. The channel length is shown to get longer by the recess region 60.
However, as the semiconductor device becomes smaller, there is a limit to increasing the channel length using the recess region, and also it becomes difficult to create a subsequent landing plug contact region. Since the width of the recess region becomes smaller and the depth of the recess region becomes deeper to obtain a predetermined channel length, the process margin for forming the recess region has been lessened.